A bicategorical approach to information flow and security

In [D. Sutherland, in Proceedings of the 9th National Computer Security Conference (Gaithersburg, MD, 1986), 175–183, National Bureau of Standards, Gaithersburg, MD, 1986] a model of information flow and security was established and investigated. The model consists of sets S, A, B and mappings f: S −!A and g: S −!B; an element s 2 S is a complete description of the state of a system, f(s) [or g(s)] is the information about s available to the first [or second] user. The measure of security is based on what facts we can deduce about s from knowledge of f(s) [or g(s)]. The paper generalizes this model to the language of category theory. First generalizations of the model to languages of the category of all sets and the category of all relations or to languages of the category of all posets and the category of all ideals are presented and discussed. From this, a generalization to general locally-ordered bicategories is suggested